Phenothiazine drugs as novel and eco-friendly corrosion inhibitors for copper in sulfuric acid solution

Abstract Two phenothiazine drugs, perphenazine (PPZ) and chlorpromazine hydrochloride (CPZ), which contain N, S multiple active sites could be co-adsorbed on the copper surface, so they can play a certain preservative effect for copper in sulfuric acid solution. Therefore, their inhibition performance was studied by means of electrochemical tests, surface analysis and theoretical calculations. The results show that both drugs are cathodic corrosion inhibitors, and the corrosion inhibition efficiency can reach 94.9% and 97.2%, respectively. And the inhibition effect of CPZ is greater than PPZ. Besides, corrosion inhibition efficiency increases with increasing inhibitor concentration. In addition, both inhibitors can form a protective film on the copper surface and follow the Langmuir adsorption model. The theoretical calculation also explains the corrosion inhibition mechanism, and the results obtained are consistent with the experiment.